The aim of the present study was to investigate the colonic mucosal and cytobrush sample mRNA expression of IL-1β, IL-2, IL-12p40, IL-23p19, TNF-α and C‐C motif chemokine ligand (CCL28), using real-time RT-PCR, as well as the correlations of mRNA expression in the colonic mucosa with the cytobrush samples of dogs with large intestinal IBD. Here, IL1B is linked to inflammatory bowel disease.